Pressure measuring devices such as sphygmomanometers, that are used to measure the arterial blood pressure of a patient, typically include a pneumatic bulb which inflates a pressure chamber of an attached sleeve that is fitted over a limb (i.e., an arm or a leg) of the patient. A diaphragm or bellows assembly, responsive to changes in fluid pressure of the pneumatic bulb and the sleeve pressure chamber, is positioned in a gage housing which is fluidly connected to the pressure chamber of the sleeve through flexible tubes or hoses. In a mechanical gage housing, a pointer of a dial indicator is interconnected to the bellows assembly through a movement mechanism that is retained within the gage housing, whereby inflation of the bellows causes corresponding circumferential movement of the pointer, enabling a blood pressure measurement procedure to be carried out by a caregiver.
Typically, the above referred to movement mechanisms are quite intricate and complex, and are akin in terms of their manufacture and precision to Swiss watches. For example, and in one such movement mechanism, a pair of diaphragm springs are attached adjacent opposing ends of a spindle. A bottom end of the spindle is placed in contact with the bellows assembly and a twisted bronze band perpendicularly disposed at the top end of the spindle is connected in parallel by a horizontally disposed spring bent part. As the spindle deflects axially in response to the inflation of the bellows, the bent spring part is also caused to deflect, thereby causing the band to twist. The pointer, attached to the bronze band, therefore is caused to rotate in relation to an adjacent dial face.
Devices, such as the foregoing, include numerous moving and relatively complex components, some or each of having numerous bearing surfaces. Therefore, such known devices must be manufactured with relatively strict tolerance margins and significant associated costs in terms of both precision and failure rate in order to minimize errors.
In addition, any adjustments required after assembly of the above mechanisms, such as to null the pointer or adjust the sensitivity of the device, require substantial tear down or at least some undesired disassembly.
Furthermore, discrete and separate elements are typically required within the instrument housing for independently supporting the movement mechanism and the bellows assembly, respectively, and for defining an expansion chamber for the bellows assembly there between.
A more recent and simplified movement mechanism is described in U.S. Pat. No. 5,996,829, incorporated by reference in its entirety. This mechanism includes a vertically disposed axial cartridge having a spirally wrapped ribbon spring with one end mounted to an axially movable elongate shaft and the remaining end of the spring being attached to a fixed tubular sleeve. A bottom portion of the elongate shaft is positioned relative to an expandable diaphragm or bellows, wherein subsequent axial translation of the shaft, caused by movement of the diaphragm, elongates the spirally wound ribbon spring and produces repeatable circumferential movement of a pointer supported at the top end of the shaft. The above movement mechanism is far smaller and more lightweight than those previously known due to its simplified construction.
A further advance, described in U.S. Pat. No. 6,168,566, also incorporated by reference in its entirety, permits the design of a housing retaining the movement mechanism described in the '829 patent to be even more compact.
One feature common to the above pressure measuring devices is the need to fluidly interconnect the gage housing containing the movement mechanism, the dial face and the indicating member with the interior of the inflatable sleeve. This interconnection is typically done using an elongated hose that is connected to a barb or coupling located on the sleeve exterior at one end of the hose and to an inlet port disposed on one end of the gage housing. It is a general object in the field to simplify the manufacture of these devices and to better integrate the design thereof.
More recently, electronic versions of pressure measuring devices have become much more prevalent and conspicuous in their use in the field. These devices such as those manufactured by Omron, Inc. among others can be mounted to the arm or wrist of a patient. These devices have a battery powered electronically based device that converts the output from the sleeve into a pressure reading output to the user. There is still reliance, however, upon inflation and deflation of an inflatable sleeve and more particularly, there is a fluid interconnection between the interior of the sleeve and the interior of the gage housing. In addition and to date, all of these devices have always been part of an integrated assembly, including the sleeve, whereby replacement has required replacement of not only the sleeve, but also the tethered electronic components.
With the emergence of such electronic equipment, there are now numerous effective ways to measure blood pressure through use of a variety of different types of both manual and electronic blood pressure measurement equipment and devices. There are two general types of manual or mechanical blood pressure measurement equipment that remain in circulation and that continue to be manufactured and used indiscriminately today. A first type of measurement device is in communication with a cuff/sleeve through a single lumen hose attachment that is utilized to inflate and deflate pressure in the cuff. A second type of blood pressure measurement device is in communication with a cuff/sleeve through a dual lumen hose attachment in which one lumen is again utilized to inflate and deflate pressure in the cuff and the second lumen allows for monitoring of the pressure within the cuff. Similarly, there are also different types of electronic blood pressure measurement devices, some of which rely upon hose attachments having one lumen, and others that utilize a dual lumen hose attachment. Moreover, some manufacturers have designed manual and electronic blood pressure measurement equipment that is connected to a hose attachment by one type of connector (e.g., a screw/luer type), whereas other manufacturers may require such connection be made to their equipment via a different type of connector (e.g., a luer lock or bayonet type).
Currently, there is no standard that dictates how manual or electronic blood pressure measurement devices must be designed. Moreover, hospitals and HMO treatment centers have varying needs and are budget conscious to an extent whereby most have not withdrawn older, still functioning blood pressure measurement devices from use despite also having begun to utilize newer, more sophisticated equipment. These circumstances have led to a situation in which many hospitals and HMO treatment centers have several different types (e.g., manual, electronic, reliant upon a single lumen hose attachment, reliant upon a dual lumen hose attachment, utilizing different connectors, etc.) of blood pressure measurement equipment for use at various stations on their premises.
The preceding situation, in turn, has created a problem in which vital time and manpower is being lost while switching between and among these different types of blood pressure measurement equipment. Although this problem can exist in any medical setting, it is most salient within a hospital environment, where it is often important to continually monitor the blood pressure of a patient, since a sudden change in the patient's blood pressure could be indicative of an improvement or set back in the patient's condition, or could aid in the overall diagnostic and/or treatment thereof.
At present, such continuous monitoring is generally commenced by wrapping a first cuff/sleeve (having at least one pre-attached single lumen or dual lumen hose) onto a patient in order to take the patient's blood pressure through use of a first blood pressure measurement device, either within an ambulance during transport to a hospital or upon arrival at the initial assessment/treatment area (e.g., triage unit, diagnosis station) of a hospital. It is generally necessary to remove the initial cuff/sleeve and attached hose combination prior to transporting the patient to his or her next destination within the hospital, e.g., a trauma room or an imaging room, at which a new sleeve (again with at least one single lumen or dual lumen pre-attached hose) of the proper size must be located and attached to enable blood pressure monitoring to continue through use of a different blood pressure measurement device. For example, the first blood pressure measurement device may be a manual or electronic device and the second an incompatible (e.g., due to the number of lumens in the pre-attached hose, the connector required, etc.) manual or electronic blood pressure device.
Under typical circumstances, such detaching, locating and reattaching steps might be performed several times while the patient is being initially evaluated and/or after the patient is admitted to the hospital. This is because, as noted above, many hospitals routinely utilize both manual and electronic blood pressure measurement equipment, some or all of which may be incompatible the with the currently worn cuff/sleeve with at least one hose attachment (e.g., due to being manual versus electronic, the type of connector required, the number of lumens within the attached hose, etc.). Even in a best-case scenario, each round of detaching, locating and reattaching steps are inconvenient because they command the attention, however brief, of medical personnel who could otherwise be performing different tasks. And at worst, the seconds to minutes that can be spent in locating, attaching, detaching and reattaching each new cuff/sleeve with a pre-attached hose could have life-impacting consequences for a patient.
Moreover, due to the chaos that often can be encountered when evaluating a patient in a hospital, especially in an emergency department setting, it is not uncommon for the at least one pre-attached hose that is connected to the cuff/sleeve to become kinked to an extent that would prevent further blood measurements from being taken with sufficient accuracy. Because the hose is pre-attached to the sleeve, once kinking occurs it might becomes necessary to remove the sleeve with pre-attached hose and then to locate and attach an entirely new sleeve with its own pre-attached hose. This is problematic for the same reasons noted above, plus it can introduce even more chaos into the emergency department environment.
Thus, there is a need for a procedure to reliably measure blood pressure and that also will better enable a wide range of electronic or manual blood pressure measurements to be taken interchangeably and with minimal disruptions through use of a wide range of manual or electronic blood pressure measurement equipment and devices, such as those found in a hospital or HMO treatment center environment.